GABAA VS. GABAB Modulation of Septal-Hippocampal Interconnections

Abstract

In rats, intraseptal injection of the GABA receptor agonist muscimol decreases the turnover rate of acetylcholine (TRACh) in the hippocampus in a dose-dependent and bicuculline-reversible manner (15). This is in keeping with the histochemical evidence of a substantial GABAergic innervation of the septal nuclei (11). Furthermore, stimulation of other septal neurotransmitter receptors (e.g., dopamine and beta-endorphin) can decrease the hippocampal TRACh via an activation of GABAergic interneurons (for review see 4). Conversely, some neurotransmitters, such as substance P, modulate the cholinergic activity of this pathway independently from GABAergic mechanisms.